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Cloudy outlook for albedo?

Filed under: — group @ 22 February 2006

Guest Commentary by George Tselioudis (NASA GISS)

In the past few years several attempts have been made to assess changes in the Earth’s planetary albedo, and claims of global dimming and more recently brightening have been debated in journal articles and blogs alike. In a recent article entitled “Can the Earth’s Albedo and Surface Temperatures Increase Together,” that appeared in EOS, Enric Palle and co-authors use recently released cloud data from the International Satellite Cloud Climatology Project (ISCCP) to explain how it is possible for the Earth to be warming even as it’s albedo is increasing. The need for an explanation arises from the author’s claim that the earth’s albedo has increased since the year 2000, an increase that was not followed by a decrease in surface temperature. They base this claim on Earthshine data (a measurement of the glow of the dark side of the moon that they use to deduce the earth’s reflectance) and on an albedo proxy derived from ISCCP parameters after they are regressed with two years of overlapping, but not global, earthshine observations. Subsequently they claim that the rising reflectance of the Earth has not led to a reversal of global warming because the difference between low and middle-plus-high ISCCP clouds has increased in the last four years. This they say implies that as the low-level, cooling clouds have decreased during the most recent years, the high-level, warming clouds have increased even more negating any potential cloud-induced cooling.

There are several issues connected to the use of earthshine data to calculate the earth’s albedo that have been discussed in peer-reviewed publications and that I will not discuss in this posting. I will say a few things, however, about the selective use of ISCCP data in this article to construct qualitative arguments that do not stand up to detailed quantitative analysis . More »

Sir Nicholas Shackleton

Filed under: — Ray Bradley @ 21 February 2006

With the recent death of Sir Nicholas Shackleton, paleoclimatology lost one of its brightest pioneers. Over the last ~40 years, Nick made numerous far-reaching contributions to our understanding of how climates varied in the past, and through those studies, he identified factors that are critically important for climate variability in the future. His career neatly encompasses the birth of the new science of paleoceanography to its synthesis into the even newer science of ‘Earth Systems'; he made major contributions to these evolving fields throughout his life, and his insightful papers are required reading for students of paleoclimatology.
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Happy Birthday, Charles Darwin!

Filed under: — raypierre @ 16 February 2006

Charles Darwin was born on February 12, 1809. The events commemorating Darwin’s birthday anniversary last Sunday, together with the recent conclusion of an important court case concerning the teaching of Intelligent Design (ID) in public schools prompts me to some musing concerning the relation of the Evolution/ID dialog to similar issues arising in connection with anthropogenic global warming. The age of the two theories is similar as well: Darwin introduced his theory in 1859, whereas Fourier initiated the study of the effect of atmospheres on climate with his 1821 treatise, stimulating the chain of developments leading to Arrhenius’ enunciation in 1896 of the theory that human influences on the atmosphere’s CO2 content could change the climate.

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Richard Lindzen’s HoL testimony

Filed under: — gavin @ 14 February 2006

Prof. Richard Lindzen (MIT) is often described as the most respectable of the climate ‘sceptics’ and is frequently cited in discussions here and elsewhere. Lindzen clearly has many fundamentally important papers under his belt (work on the QBO and basic atmospheric dynamics), and a number of papers that have been much less well received by the community (the ‘Iris’ effect etc.). Last year, he gave evidence to and answered questions from, a UK House of Lords Committee investigating the economics of climate change, in which he discoursed freely on the science. I’ll try here to sort out what he said. More »

James Lovelock’s Gloomy Vision

Filed under: — david @ 13 February 2006

James Lovelock, renegade Earth scientist and creator of the Gaia hypothesis, has written a gloomy new book called “Revenge of Gaia”, in which he argues that we should be stashing survival manuals, printed on good old-fashioned paper, in the Arctic where the last few breeding pairs of humans will likely be found after a coming climate catastrophe. The book is not published in the U.S. yet, but it is available from amazon.co.uk. Lovelock has never been one to shrink from a bold vision. What is it he sees now?

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